ul.thumbnails.image_picker_selector {
    white-space: nowrap;
    overflow-x: scroll;
}

ul.thumbnails.image_picker_selector li {
    float: none;
    display: inline-block;
    vertical-align: top;
    margin: 0 12px 16px 0;
    padding-left: 0;
}

ul.thumbnails.image_picker_selector li::before {
    content: none;
}

ul.thumbnails.image_picker_selector li:last-child {
    margin-right: 0;
}

ul.thumbnails.image_picker_selector li .thumbnail {
    padding: 4px;
    margin: 0;
}

ul.thumbnails.image_picker_selector li .thumbnail:hover {
    cursor: pointer;
}